(Spoiler alert: Don’t read this if you haven’t seen last Sunday’s penultimate episode.)

On the upside, the most gut-wrenching show in recent memory will soon be over.

After five seasons and 62 episodes,
Breaking Bad
— the gloomy drama about a high school science teacher turned drug kingpin turned broken man — ascends into TV heaven with a 75-minute finale on Sunday at 9 p.m. on AMC.

That’s also the downside: it’s time for Walter White (Bryan Cranston) to go.

Good shows hold our attention. Great ones capture our imagination. Since it debuted in 2008,
Breaking Bad
has been the television equivalent of crystal meth: potent, addictive and mood altering. (The show has had record ratings in its last two episodes, with 6.6 million viewers last Sunday.)

There are lots of people who never watched an episode. But there aren’t many who started watching and then stopped. For fans, the last few weeks have transcended the usual roller-coaster ride: creator Vince Gilligan has strapped us into a rocket ship and fired us into the blackest part of his dystopian galaxy.

Walt once said, “Chemistry is the study of transformation.” The same is true for characterization. So now we get to see how this saga ends, how these characters are transformed.

Here are 20 questions, grouped by chemical elements, to consider before the finale:

Element: Aluminum

No. 1: Why did Walt return to Albuquerque?

So this is it, one last showdown on the scorched plains of New Mexico. From the flash-forward in the episode “Blood Money,” we know Walt returns to his old house to snatch the ricin capsule stashed behind an electrical socket. We also know he’s heavily armed and has nothing left to lose.
No. 2:
Where is he going?
No. 3:
Who is in the “line of fire,” the title of the Junip song used in the promo?
No. 4:
Does he plan to kill Uncle Jack, Todd, Jesse, Lydia or maybe just himself?

Element: Bromine

No. 5: Is Jesse still imprisoned in the dungeon?

If we assume Walt spent a few weeks or months living in that New Hampshire cabin, this means Jesse might still be enslaved in the neo-Nazi bunker. Near the end of “Granite State,” following his botched escape, Jesse screams at Todd and his captors. He asks to be killed and insists he’s done cooking meth.
No.
6.
Can he escape a second time?
No.
7.
Or does Walt rescue him — as he’s done before in both “Half Measures” and “Face Off” — and will this lead to a final confrontation?

Element: Chlorine

No. 8: Who will deal with Todd?

He shot and killed 14-year-old Drew Sharp after the train heist in “Dead Freight.” He put a bullet in Andrea’s head last week. If AMC ever did a prequel about Todd’s childhood years, the show would be nothing but animal cruelty and pyromania. Walt started doing bad things for a good reason. Todd does bad things out of natural impulse.
No. 9:
Will he pay for his crimes?
No.
10:
Will he be killed and, if so, who will do it?

Element: Dysprosium

No. 11: How do Elliott and Gretchen factor into the final storyline?

And just when we’d forgotten about Gray Matter Technologies — damn you, Charlie Rose!
No. 12.
How do we interpret the closing scene in the penultimate episode? Did Walt change his mind about surrendering after hearing Elliott and Gretchen all but erase him from the history of Gray Matter, the company he co-founded?
No. 13.
Or is he reacting to her observation — “The sweet, kind, brilliant man that we once knew long ago, he’s gone” — and determined to prove she’s wrong by exerting his true identity, exorcising Heisenberg and writing his own history?

Element: Einsteinium

No. 14. Can Walt and Jesse reconcile?

Remember back to “Cat’s in the Bag” and the unlikely friendship that gestated between Jesse and Mr. White? They had real chemistry. Now the relationship is as toxic as phosphine gas. Jesse wanted out of the meth game since “Say My Name.” From brash and funny, to dour and conflicted, to miserable and catatonic, his life has become a living hell. He blames Walt for this.
No.
15:
Even if he can’t forget, can Jesse forgive?
No.
16:
Are the former meth producers locked inside a zero sum game of mutual destruction in which only one can survive?
No. 17:
Will Jesse kill Walt?

Element: Francium

No. 18. Is the White family permanently broken?

The last time Walter was with wife Skyler, she lunged at him with a knife. The last time he heard his son’s voice, Walt Junior yelled at him to die. The last time he saw his baby daughter, Holly, he abandoned her at a fire station. Walt only ventured into the meth business to leave a “nest egg” for his family following his terminal cancer diagnosis. Now most of his $80-million fortune has been stolen and his family, like Elliott and Gretchen, wants to pretend he never existed. Based on the first 61 episodes, it’s safe to assume there will be no happy ending.
No. 19:
But can Walt hit the stop button on the emotional blender he tossed his family inside?
No. 20:
Is there any possibility of redemption?

More on thestar.com

We value respectful and thoughtful discussion. Readers are encouraged to flag comments that fail to meet the standards outlined in our
Community Code of Conduct.
For further information, including our legal guidelines, please see our full website
Terms and Conditions.